A Randomized, Multicenter, Double-Blind, Placebo-Controlled Phase II Study of the Efficacy and Safety of Trastuzumab Emtansine in Combination With Atezolizumab or Atezolizumab-Placebo in Patients With HER2-Positive Locally Advanced or Metastatic Breast Cancer Who Have Received Prior Trastuzumab and Taxane Based Therapy

This Phase II, double-blind, randomized, placebo-controlled multicenter study will
investigate the efficacy and safety of trastuzumab emtansine in combination with atezolizumab
or atezolizumab-placebo in participants with HER2-positive locally advanced or metastatic BC
who have received prior trastuzumab and taxane based therapy, either alone or in combination,
and/or who have progressed within 6 months after completing adjuvant therapy.

本项II期、双盲、随机、安慰剂对照多中心研究，将针对既往接受过以曲妥珠单抗和紫杉类为基础的单一或联合治疗，且/或在完成辅助治疗后6个月内出现疾病进展的HER2阳性局部晚期或转移性乳腺癌（Breast Cancer，BC）受试者，评估恩美曲妥珠单抗（trastuzumab emtansine）联合阿替利珠单抗（atezolizumab）或阿替利珠单抗-安慰剂方案的疗效与安全性。